Galloping of an iced transmission line subjected to a moderating airflow has been analysed in this study, and a new form of galloping is discovered both theoretically and experimentally. The partial differential equations of the iced transmission line are established based on the Hamilton theory. The Galerkin method is then applied on the continuous model, and a discrete model is derived along with its first two in-plane and torsional modes. A trapezoidal wind field model is built through the superposition of simple harmonic waves. The vibrational amplitude is generally observed to be more violent when the wind velocity decreases, except in the 2^nd in-plane mode. Furthermore, the influence of the declining wind velocity rates on galloping is analysed using different postdecline wind velocities and the duration of the decline in wind velocities. Subsequently, an experiment has been carried out on a continuous model of an iced conductor in the wind tunnel dedicated for galloping. The first two in-plane modal profiles are observed, along with their response to the moderating airflow. Different declining rates of the wind velocity are also verified in the wind tunnel, which show good agreement with the results simulated by the mathematical model. The sudden increase in the galloping amplitude poses a significant threat to the transmission system, which also improves the damage mechanism associated with the galloping of a slender, a long structure with a noncircular cross-section.

中文翻译：

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冰冻输电线路在缓速气流中飞驰的理论分析与实验验证

本研究分析了受减速气流影响的结冰传输线的飞驰，并在理论和实验上发现了一种新的飞驰形式。基于Hamilton理论建立了冰冻传输线的偏微分方程。然后将 Galerkin 方法应用于连续模型，并导出离散模型及其前两个平面内和扭转模式。通过简谐波的叠加建立梯形风场模型。当风速减小时，一般观察到振动幅度更剧烈，除了在^第二面内模式。此外，使用不同的下降后风速和风速下降的持续时间分析了下降风速率对疾驰的影响。随后，在专用于飞驰的风洞中对冰导体的连续模型进行了实验。观察前两个平面内模态分布，以及它们对调节气流的响应。在风洞中也验证了不同的风速下降率，与数学模型模拟的结果吻合良好。飞驰幅度的突然增加对传动系统构成了重大威胁，这也改善了与具有非圆形横截面的细长结构的飞驰相关的损坏机制。